title: Raman evidence for orbiton-mediated multiphonon scattering in multiferroic TbMnO3.
abstract: Temperature-dependent Raman spectra of TbMnO(3) from 5 to 300 K in the spectral range of 200-1525 cm(-1) show five first-order Raman allowed modes and two high frequency modes. The intensity ratio of the high frequency Raman band to the corresponding first-order Raman mode is nearly constant and high (∼0.6) at all temperatures, suggesting an orbiton-phonon mixed nature of the high frequency mode. One of the first-order phonon modes shows anomalous softening below T(N) (∼46 K), suggesting a strong spin-phonon coupling.
authors.affiliation: Department of Physics, Indian Institute of Science, Bangalore-560012, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
authors.forename: Surajit
authors.initials: S
authors.lastname: Saha
authors.forename: D V S
authors.initials: DV
authors.lastname: Muthu
authors.forename: J R
authors.initials: JR
authors.lastname: Sahu
authors.forename: A K
authors.initials: AK
authors.lastname: Sood
authors.forename: C N R
authors.initials: CN
authors.lastname: Rao